From e287af83fffad1617e6d4f3205d725be9be97919 Mon Sep 17 00:00:00 2001
From: Neil McKechnie <neilmck999@gmail.com>
Date: Wed, 22 Sep 2021 10:38:11 +0100
Subject: [PATCH] DCC Turnouts: Store address/subaddress separately.  Enable
 address 0.

The range of accessory decoder addresses for the <a> command is 0-511 in line with the DCC packet contents.  The turnout command previously rejected address 0; this has been changed to the same range of addresses can be used by both commands, i.e. address 0-511 and subaddress 0-3.  The linear address mapping remains so that linear address 1 is addr/subaddr 1/0; i.e. the first decoder address is not accessible by linear address.
---
 DCCEXParser.cpp |  8 +++++---
 Turnouts.cpp    | 17 ++++++++---------
 Turnouts.h      |  8 +++++---
 3 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/DCCEXParser.cpp b/DCCEXParser.cpp
index d09aa1b..b5f472f 100644
--- a/DCCEXParser.cpp
+++ b/DCCEXParser.cpp
@@ -736,15 +736,17 @@ bool DCCEXParser::parseT(Print *stream, int16_t params, int16_t p[])
         if (!VpinTurnout::create(p[0], p[2])) return false;
       } else 
       if (params >= 3 && p[1] == HASH_KEYWORD_DCC) {
-        if (params==4 && p[2]>0 && p[2]<=512 && p[3]>=0 && p[3]<4) { // <T id DCC n m>
+        // <T id DCC addr subadd>   0<=addr<=511, 0<=subadd<=3 (like <a> command).<T>
+        if (params==4 && p[2]>=0 && p[2]<512 && p[3]>=0 && p[3]<4) { // <T id DCC n m>
           if (!DCCTurnout::create(p[0], p[2], p[3])) return false;
         } else if (params==3 && p[2]>0 && p[2]<=512*4) { // <T id DCC nn>, 1<=nn<=2048
+          // Linearaddress 1 maps onto decoder address 1/0 (not 0/0!).
           if (!DCCTurnout::create(p[0], (p[2]-1)/4+1, (p[2]-1)%4)) return false;
         } else
           return false;
       } else 
-      if (params==3) { // legacy <T id n n> for DCC accessory
-        if (p[1]>0 && p[1]<=512 && p[2]>=0 && p[2]<4) {
+      if (params==3) { // legacy <T id addr subadd> for DCC accessory
+        if (p[1]>=0 && p[1]<512 && p[2]>=0 && p[2]<4) {
           if (!DCCTurnout::create(p[0], p[1], p[2])) return false;
         } else
           return false;
diff --git a/Turnouts.cpp b/Turnouts.cpp
index 6dbc402..dcbff73 100644
--- a/Turnouts.cpp
+++ b/Turnouts.cpp
@@ -340,7 +340,8 @@
   DCCTurnout::DCCTurnout(uint16_t id, uint16_t address, uint8_t subAdd) :
     Turnout(id, TURNOUT_DCC, false)
   {
-    _dccTurnoutData.address = ((address-1) << 2) + subAdd + 1;
+    _dccTurnoutData.address = address;
+    _dccTurnoutData.subAddress = subAdd;
   }
 
   // Create function
@@ -351,7 +352,8 @@
       if (tt->isType(TURNOUT_DCC)) {
         // Yes, so set parameters<T>
         DCCTurnout *dt = (DCCTurnout *)tt;
-        dt->_dccTurnoutData.address = ((add-1) << 2) + subAdd + 1;
+        dt->_dccTurnoutData.address = add;
+        dt->_dccTurnoutData.subAddress = subAdd;
         // Don't touch the _closed parameter, retain the original value.
         return tt;
       } else {
@@ -371,27 +373,24 @@
     EEStore::advance(sizeof(dccTurnoutData));
     
     // Create new object
-    DCCTurnout *tt = new DCCTurnout(turnoutData->id, (((dccTurnoutData.address-1) >> 2)+1), ((dccTurnoutData.address-1) & 3));
+    DCCTurnout *tt = new DCCTurnout(turnoutData->id, dccTurnoutData.address, dccTurnoutData.subAddress);
 
     return tt;
   }
 
   void DCCTurnout::print(Print *stream) {
     StringFormatter::send(stream, F("<H %d DCC %d %d %d>\n"), _turnoutData.id, 
-      (((_dccTurnoutData.address-1) >> 2)+1), ((_dccTurnoutData.address-1) & 3), 
-      !_turnoutData.closed); 
+      _dccTurnoutData.address, _dccTurnoutData.subAddress, !_turnoutData.closed); 
     // Also report using classic DCC++ syntax for DCC accessory turnouts, since JMRI expects this.
     StringFormatter::send(stream, F("<H %d %d %d %d>\n"), _turnoutData.id, 
-      (((_dccTurnoutData.address-1) >> 2)+1), ((_dccTurnoutData.address-1) & 3), 
-      !_turnoutData.closed); 
+      _dccTurnoutData.address, _dccTurnoutData.subAddress, !_turnoutData.closed); 
   }
 
   bool DCCTurnout::setClosedInternal(bool close) {
     // DCC++ Classic behaviour is that Throw writes a 1 in the packet,
     // and Close writes a 0.  
     // RCN-213 specifies that Throw is 0 and Close is 1.
-    DCC::setAccessory((((_dccTurnoutData.address-1) >> 2) + 1), 
-      ((_dccTurnoutData.address-1) & 3), close ^ !rcn213Compliant);
+    DCC::setAccessory(_dccTurnoutData.address, _dccTurnoutData.subAddress, close ^ !rcn213Compliant);
     _turnoutData.closed = close;
     return true;
   }
diff --git a/Turnouts.h b/Turnouts.h
index 9c14089..6a55c15 100644
--- a/Turnouts.h
+++ b/Turnouts.h
@@ -213,9 +213,11 @@ private:
   // DCCTurnoutData contains data specific to this subclass that is 
   // written to EEPROM when the turnout is saved.
   struct DCCTurnoutData {
-    // DCC address (Address in bits 15-2, subaddress in bits 1-0
-    uint16_t address; // CS currently supports linear address 1-2048
-      // That's DCC accessory address 1-512 and subaddress 0-3.
+    // DCC address (Address in bits 15-2, subaddress in bits 1-0)
+    struct {
+      uint16_t address : 14;
+      uint8_t subAddress : 2;
+    };
   } _dccTurnoutData; // 2 bytes
 
   // Constructor